This invention relates generally to the engine field and, more specifically, to a new and useful variable valve mechanism for an engine.
In conventional engines, a rotating cam pushes a valve from a closed position to an open position. The open position of the valve typically allows a fuel-and-air mixture into a cylinder or allows a combusted mixture out of the cylinder. The closed position of the valve typically allows a spark to combust the fuel-and-air mixture. In a conventional engine, the valve must open and close at a rate up to nearly 90 cycles per second. For this reason, a biasing device, such as a coil spring, swiftly pushes the valve from the open position into the closed position after sufficient rotation of the cam.
Recent progress in the engine field suggests the use of a variable valve mechanism to selectively open and close valves based upon several data signals, such as emissions data. Some systems to pursue this goal have used a dual electromagnet arrangement: one to magnetically pull an armature connected to a valve from a closed position into an open position and one to magnetically pull the valve from the open position to the closed position. These systems, such as the system found in U.S. Pat. No. 6,269,784 entitled xe2x80x9cElectrically Actuable Engine Valve Providing Position Outputxe2x80x9d, issued on Aug. 7, 2001, and incorporated by this reference in its entirety, have increased fuel economy and decreased start-up emissions. These systems, however, have typically suffered from cost and noise-vibration-harshness (NVH) problems.
Thus, there is a need in the engine field to create a new and useful variable valve mechanism.